The present invention relates to multiple contact connectors. More particularly, the invention relates to multiple contact connectors for the termination of flexible flat conductor means such as flexible flat cable and flexible etched circuitry.
Conventionally, flexible flat conductor cable has a plurality of flat, ribbon-like conductors embedded in an insulating medium, e.g., polyester, wherein the conductors lie generally parallel to each other in a single plane.
Flexible flat conductor cable is being used in wiring applications to an increasing extent as a result of its compactness and advantageous electrical characteristics. For example, it has been found that this type of cable may very easily be replaced and/or installed under relatively crowded conditions which would render other conventional wiring arrangements costly, burdensome, and subject to wiring errors. However, the commercial utility of flexible flat conductor cable has been hampered by the lack of a particularly suitable termination contact.
In the past, connector devices for flat conductor cable have been provided which utilize both crimp-type terminations and solder-type terminations. In the case of many of these devices, it has been necessary to prepare a portion of the cable in order to receive the connector. For example, in many instances it is necessary to strip the insulation from the end of the cable prior to application of the contact to the cable. In other instances, the cable may require a pre-perforation to accommodate a portion of the contact (see e.g., U.S. Pat. Nos. 3,675,180 or 3,768,062).
In the use of yet other devices, it is not necessary to remove a portion of the insulation material. The insulation may be pierced by a contact which straddles a conductor of the cable. The contact may then be crimped to the conductor to effect an electrical connection (see U.S. Pat. No. 3,395,381). This prior art arrangement may in some instances require a relatively large interspace between the plurality of parallel, ribbon-like conductors which make up the cable. Moreover, these prior art connecting devices, by virtue of their straddling relationship with the conductors, require a crimp in a direction generally transverse to a longitudinal axis of the conductor. Thus, if the width of the conductors varies, the contact width must be varied to accommodate that width; and, if an attempt is made to standardize the contact width, the utility of the contact would be limited or significant conductor cable preparation would be required.
In addition, such prior art connecting devices dictate the maintenance of critical tolerances, and often result in formation of slivers of conductor cable by unintended shaving of the conductor during application of the contact. Furthermore, simultaneous termination is difficult if not impractical, and, if a large number of contacts are to be employed, flow of the plastic insulating material could adversely displace the conductors of the cable from their intended location.
The present invention falls into the category of terminating devices for flexible flat conductor cable wherein the insulation is pierced and substantially no prior preparation of the cable is necessary at the location chosen to terminate the cable.
There has been suggested in the prior art a terminal for flexible circuits which has tangs intended to penetrate the full thickness of the flexible circuit in order to thereby "staple" the terminal onto the flexible circuit at a pre-perforated location (see U.S. Pat. No. 3,768,062).
The device disclosed in the U.S. Pat. No. 3,768,062, proposes a terminal for flexible circuits which rests on a rim portion of the terminal extending generally normal to a generally planar base portion. According to this proposal, tangs, which are formed from an extension of the rim, penetrate the full thickness of the flexible circuit at a pre-perforated zone of enlarged width on the flexible circuit. After penetrating through the circuit, the tangs are bent against an outer layer of the circuit. It has been further suggested that, if desired, these tangs upon attachment of the terminal could be driven against an anvil of suitable configuration to provide reentry of the tangs into the flexible circuit.
It will be appreciated that these and other crimpable connecting devices for flat conductor cable in the prior art require that some extraordinary preparation be made in the cable or circuit being terminated to accommodate the connector, or that a cable having relatively wide interspaces between the conductors be chosen to prevent adjacent connectors from making electrical contact. These factors may significantly limit the utility of the cable or circuit used and, in addition, impose substantial economic restraints on the utilization of the cable or circuit. Moreover, these prior art connectors may form an electrical contact which may have certain undesirable characteristics. For example, the electrical contact made between prior art connecting devices and the conductor cable may occur over an insufficient number of points to perform satisfactorily. In addition, these prior art connectors may not provide a sufficiently tight mechanical engagement of the conductor to produce a satisfactory electrical contact over a relatively long life.
It would, therefore, be desirable to provide a novel method and apparatus for terminating flexible flat conductor cables which minimizes or reduces at least the problems of the type previously noted in connection with prior art devices.